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Chronic Lymphocytic Leukemia Treatment (PDQ®)

General Information About Chronic Lymphocytic Leukemia (CLL)

Incidence and Mortality

Estimated new cases and deaths from CLL in the United States in 2015:[1]

New cases: 14,620.

Deaths: 4,650.

CLL is a disorder of morphologically mature but immunologically less mature lymphocytes and is manifested by progressive accumulation of these cells in the blood, bone marrow, and lymphatic tissues.[2] In this disorder, lymphocyte counts in the blood are usually greater than or equal to 5,000/mm3 with a characteristic immunophenotype (CD5- and CD23-positive B cells).[3,4] As assays have become more sensitive for detecting monoclonal B-CLL–like cells in peripheral blood, researchers have detected a monoclonal B-cell lymphocytosis (MBL) in 3% of adults older than 40 years and 6% in adults older than 60 years.[5] Such early detection and diagnosis may falsely suggest improved survival for the group and may unnecessarily worry or result in therapy for some patients who would have remained undiagnosed in their lifetime, a circumstance known in the literature as overdiagnosis or pseudodisease.[6,7]

In two selected series of more than 900 patients followed prospectively for a median of 5 to 7 years, overt CLL requiring chemotherapy occurred in 7% of patients.[5,8] In a database analysis and for up to 77 months before diagnosis, almost all patients with a diagnosis of CLL had prediagnostic B-cell clones that were identified in peripheral blood when available.[4,9]

For patients with progressing CLL, treatment with conventional doses of chemotherapy is not curative; selected patients treated with allogeneic stem cell transplantation have achieved prolonged disease-free survival.[10-14] Antileukemic therapy is frequently unnecessary in uncomplicated early disease.[15] The median survival for all patients ranges from 8 to 12 years in older trials with data from the 1970s through the 1990s.[15,16] There is, however, a large variation in survival among individual patients, ranging from several months to a normal life expectancy. Treatment must be individualized based on the clinical behavior of the disease.[17]

As found in one report, CLL occurs primarily in middle-aged and elderly adults, with increasing frequency in successive decades of life.[18] The clinical course of this disease progresses from an indolent lymphocytosis without other evident disease to one of generalized lymphatic enlargement with concomitant pancytopenia. Complications of pancytopenia, including hemorrhage and infection, represent a major cause of death in these patients.[19] Immunological aberrations, including Coombs-positive hemolytic anemia, immune thrombocytopenia, and depressed immunoglobulin levels may all complicate the management of CLL.[20] Prognostic factors that may help predict clinical outcome include cytogenetic subgroup, immunoglobulin mutational status, ZAP-70, and CD38.[2,21-29] (Refer to the Prognostic Factors section in the Stage Information for Chronic Lymphocytic Leukemia section of this summary for more information.) Patients who develop an aggressive high-grade non-Hodgkin lymphoma, usually diffuse large B-cell lymphoma and termed a Richter transformation, have a poor prognosis.[30] Patients with CLL are also at increased risk for other malignancies, even before therapy.[31]

Confusion with other diseases may be avoided by determination of cell surface markers. CLL lymphocytes coexpress the B-cell antigens CD19 and CD20 along with the T-cell antigen CD5.[32] This coexpression only occurs in one other disease entity, mantle cell lymphoma. CLL B cells express relatively low levels of surface-membrane immunoglobulin (compared with normal peripheral blood B cells) and a single light chain (kappa or lambda).[15] CLL is diagnosed by an absolute increase in lymphocytosis and/or bone marrow infiltration coupled with the characteristic features of morphology and immunophenotype, which confirm the characteristic clonal population.

The differential diagnosis must exclude hairy cell leukemia and Waldenström macroglobulinemia. (Refer to the PDQ summaries on Hairy Cell Leukemia and Adult Non-Hodgkin Lymphoma Treatment for more information.) Waldenström macroglobulinemia has a natural history and therapeutic options similar to CLL, with the exception of hyperviscosity syndrome associated with macroglobulinemia as a result of elevated immunoglobulin M. Prolymphocytic leukemia (PLL) is a rare entity characterized by excessive prolymphocytes in the blood with a typical phenotype that is positive for CD19, CD20, and surface-membrane immunoglobulin and negative for CD5. These patients demonstrate splenomegaly and poor response to low-dose or high-dose chemotherapy.[15,33]

Cladribine (2-chlorodeoxyadenosine) appears to be an active agent (60% complete remission rate) for patients with de novo B-cell prolymphocytic leukemia.[34][Level of evidence: 3iiiDiv] Alemtuzumab (campath-1H), an anti-CD52 humanized monoclonal antibody, has been used for 76 patients with T-cell prolymphocytic leukemia after failure of prior chemotherapy (usually pentostatin or cladribine) with a 51% response rate (95% confidence interval, 40%–63%) and median time to progression of 4.5 months (range, 0.1–45.4 months).[35][Level of evidence: 3iiiDiv] These response rates have been confirmed by other investigators.[36] Patients with CLL who show prolymphocytoid transformation maintain the classic CLL phenotype and have a worse prognosis than PLL patients.

Large granular lymphocyte (LGL) leukemia is characterized by lymphocytosis with a natural killer cell immunophenotype (CD2, CD16, and CD56) or a T-cell immunophenotype (CD2, CD3, and CD8).[37-39] These patients often have neutropenia and a history of rheumatoid arthritis. The natural history is indolent, often marked by anemia and splenomegaly. This condition appears to fit into the clinical spectrum of Felty syndrome.[40] A characteristic genetic finding in almost 50% of the patients with T-cell LGL involves mutations in the signal transducer and activator of the transcription 3 gene (STAT 3).[41] Therapy includes low doses of oral cyclophosphamide or methotrexate, cyclosporine, and treatment of the bacterial infections acquired during severe neutropenia.[37,39,42,43]

Related Summaries

Other PDQ summaries containing information about CLL include the following:

Stage Information for CLL

Staging is useful in chronic lymphocytic leukemia (CLL) to predict prognosis and also to stratify patients to achieve comparisons for interpreting specific treatment results. Anemia and thrombocytopenia are the major adverse prognostic variables.

CLL has no standard staging system. The Rai staging system and the Binet classification are presented below.[1,2] A National Cancer Institute (NCI)-sponsored working group has formulated standardized guidelines for criteria related to eligibility, response, and toxic effects to be used in future clinical trials in CLL.[3]

The Binet classification integrates the number of nodal groups involved with the disease with bone marrow failure. Its major benefit derives from the recognition of a predominantly splenic form of the disease, which may have a better prognosis than in the Rai staging, and from recognition that the presence of anemia or thrombocytopenia has a similar prognosis and does not merit a separate stage. Neither system separates immune from nonimmune causes of cytopenia. Patients with thrombocytopenia or anemia or both, which is caused by extensive marrow infiltration and impaired production (Rai III/IV, Binet C) have a poorer prognosis than patients with immune cytopenias.[4] The International Workshop on CLL has recommended integrating the Rai and Binet systems as follows: A(0), A(I), A(II); B(I), B(II); and C(III), C(IV).[5] The NCI-sponsored working group has published guidelines for the diagnosis and treatment of CLL in both clinical trial and general practice settings.[3] Use of these systems allows comparison of clinical results and establishment of therapeutic guidelines.

Prognostic factors

New prognostic markers are now available to the clinician and investigator.[6,7] The use of these markers to stratify patients in clinical trials, to help assess the need for therapy, and to help select the type of therapy continues to evolve. Prospective trials to verify and establish the role of these prognostic markers are ongoing. No large multivariable analyses exist as yet to test the relative power of these individual prognostic variables.[8] Prognostic indices are under evaluation and will require prospective validation.[9]

Immunoglobulin variable region heavy chain gene (IgVH) mutation.[10-14] The finding of significant numbers of mutations in this region is associated with a median survival in excess of 20 to 25 years. The absence of mutations is associated with a median survival of 8 to 10 years.

ZAP-70. ZAP-70 has been proposed as a surrogate for the mutational status.[15-18] ZAP-70 positivity for previously untreated and asymptomatic patients (>30%) is associated with a more unfavorable median survival (6–10 years), while a negative ZAP-70 is associated with a median survival of more than 15 years. A prospective evaluation of these markers in a randomized study of fludarabine-based chemotherapy (E2997 [NCT00003764]) failed to show any difference in response rates, response duration, progression-free survival, or overall survival (OS).[19]

Chromosomal abnormalities by fluorescent in situ hybridization (FISH). FISH chromosomal abnormalities were associated with prognosis in retrospective and prospective studies and clonal evolution has been seen over time.[20-23] 13q- is favorable (with a 17-year median OS in a prospective study).[23] Trisomy 12 and 11q- have less favorable prognoses (with a 9- to 11-year median OS in a prospective study).[23] In particular, 17p- is associated with mutated TP53 and with poor response rates and short duration of response to the standard therapeutic options.[13] 17p- is associated with the most unfavorable prognosis (with a 7-year median OS in one prospective trial).[19,23,24] The combination of adverse cytogenetics such as 11q- or 17p- (suggesting a worse prognosis) with ZAP-70 negativity (suggesting a better prognosis) in the same patients resulted in a poor prognosis.[18] These findings emphasize the need for prospective studies of combinations of these prognostic markers.[8]

CD38 immunophenotype.[11,25] CD38 positivity (>30%) correlates with a worse prognosis, but there is a 30% false-positive rate and a 50% false-negative rate using IgVH mutational status as the gold standard for prognosis.

Treatment Option Overview for CLL

Treatment of chronic lymphocytic leukemia (CLL) ranges from periodic observation with treatment of infectious, hemorrhagic, or immunologic complications to a variety of therapeutic options, including steroids, alkylating agents, purine analogs, combination chemotherapy, monoclonal antibodies, and transplant options.[1] Because this disease is generally not curable, occurs in an elderly population, and often progresses slowly, it is most often treated in a conservative fashion.[1] In asymptomatic patients, treatment may be deferred until the patient becomes symptomatic as the disease progresses. Since the rate of progression may vary from patient to patient, with long periods of stability and sometimes spontaneous regressions, frequent and careful observation is required to monitor the clinical course.[2]

A meta-analysis of randomized trials showed no survival benefit for immediate versus delayed therapy for patients with early stage disease, nor for the use of combination regimens incorporating an anthracycline compared with a single-agent alkylator for advanced stage disease.[3][Level of evidence: 1iiA] A variety of clinical factors, including IgVH mutation, chromosomal abnormalities by fluorescent in situ hybridization analysis or cytogenetics, beta-2-microglobulin, and lymphocyte doubling time may be helpful in predicting progression of disease.[1]

Infectious complications in advanced disease are in part a consequence of the hypogammaglobulinemia and the inability to mount a humoral defense against bacterial or viral agents. Herpes zoster represents a frequent viral infection in these patients, but infections with Pneumocystis carinii and Candida albicans may also occur. The early recognition of infections and the institution of appropriate therapy are critical to the long-term survival of these patients. A randomized study of intravenous immunoglobulin (400 mg/kg every 3 weeks for 1 year) in patients with CLL and hypogammaglobulinemia produced significantly fewer bacterial infections and a significant delay in onset of first infection during the study period.[4] There was, however, no effect on survival. Routine chronic administration of intravenous immunoglobulin is expensive, and the long-term benefit (>1 year) is unproven.[5,6]

Second malignancies and treatment-induced acute leukemias may also occur in a small percentage of patients.[7] Transformation of CLL to diffuse large cell lymphoma (Richter syndrome) carries a poor prognosis with a median survival of less than 1 year, though 20% of the patients may live more than 5 years after aggressive combination chemotherapy.[8] (Refer to the PDQ summary on Adult Non-Hodgkin Lymphoma Treatment for more information.)

Autoimmune hemolytic anemia and/or thrombocytopenia can occur in patients with any stage of CLL.[9] Initial therapy involves corticosteroids with or without alkylating agents (fludarabine can worsen the hemolytic anemia). It is frequently advisable to control the autoimmune destruction with corticosteroids, if possible, prior to administering marrow-suppressive chemotherapy because such patients may be difficult to transfuse successfully with either red blood cells or platelets. Alternate therapies include high-dose immune globulin, rituximab, cyclosporine, azathioprine, splenectomy, and low-dose radiation therapy to the spleen.[10,11] Tumor lysis syndrome is an uncommon complication (presenting in 1 out of 300 patients) of chemotherapy for patients with bulky disease.[12]

About 1% of morphologic CLL cases express T-cell markers (CD4 and CD7) and have clonal rearrangements of their T-cell receptor genes. These patients have a higher frequency of skin lesions, more variable lymphocyte shape, and shorter median survival (13 months) with minimal responses to chemotherapy.[13]

Computed tomographic (CT) scans have a very limited role in following patients after completion of treatment; the decision to treat for relapse was determined by CT scan or ultrasound in only 2 of 176 patients in three prospective trials for the German CLL Study Group.[14]

Stage 0 CLL

Because of the indolent nature of stage 0 chronic lymphocytic leukemia (CLL), treatment is not indicated.[1] The French Cooperative Group on CLL randomly assigned 1,535 patients with previously untreated stage A disease to receive either chlorambucil or no immediate treatment and found no survival advantage for immediate treatment with chlorambucil.[2][Level of evidence: 1iiA] A meta-analysis of six trials of immediate versus deferred therapy with chlorambucil (including the aforementioned trial by the French Cooperative Group) showed no difference in overall survival at 10 years.[3][Level of evidence: 1iiA] Whether immediate therapy with the nucleoside analogs or other newer strategies will be superior to a watchful waiting approach is uncertain.

Current Clinical Trials

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with stage 0 chronic lymphocytic leukemia. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

The first trial, a comparison of chlorambucil versus fludarabine, after 15 years of median follow-up, showed improved median OS for patients on the fludarabine regimen at 63 months versus 59 months (P = .04), and an improved percentage of patients were alive at 8 years (31% vs. 19%, P = .04).[3,5][Level of evidence: 1iiA]

The improvements in response rates from more intensive regimens have maximized the clearance of minimal residual disease (MRD). In one prospective trial of 493 patients, clearance of MRD was an independent predictor of OS by multivariate analysis.[6] The surrogate endpoint of such clearance of residual disease, while prognostic,[6,7] has not been shown to improve survival in a randomized prospective trial; the necessary study would take patients who fail to completely clear the marrow with induction therapy and randomly assign them to further alternative treatment versus the same treatment later at relapse, looking at OS as the primary endpoint.[1,2]

The sequencing of the following treatment options cannot be determined from the current set of completed clinical trials. When patients become symptomatic or require treatment, FCR has become the most frequently chosen option outside of a clinical trial, mostly on the basis of the previously described prospective study.[4]

Treatment options:

Note: Standard options are roughly ordered by level of toxic effects, starting with the least toxic options. More recently discovered options are mentioned at the end of the list.

Observation in asymptomatic or minimally affected patients.[8] Outside of the context of a clinical trial, treatment for asymptomatic or minimally affected patients with chronic lymphocytic leukemia (CLL) is observation. No data exist as yet to suggest any harm with a delay in therapy until the patient becomes symptomatic or develops serious cytopenias despite growth factor support. Because the rate of progression may vary from patient to patient, with long periods of stability and sometimes spontaneous regressions, frequent and careful observation is required to monitor the clinical course.

Rituximab is a murine anti-CD20 monoclonal antibody.[9-13] When used alone, higher doses of rituximab or increased frequency or duration of therapy is required for comparable responses to those seen for other indolent lymphomas.

Ofatumomab is a human anti-CD20 monoclonal antibody.[14] A trial of 138 patients, who were previously treated with fludarabine and alemtuzumab, showed overall response rates around 50% in patients refractory to fludarabine and with prior exposure to rituximab.[14,15][Level of evidence: 3iiiDiv]

Idelalisib is an oral inhibitor of the delta isoform of the phosphatidylinositol 3-kinase, which is located in the B-cell receptor-signaling cascade. In a randomized, double-blind, prospective trial (NCT01539512), 220 patients treated mainly with fludarabine-based regimens and who had coexisting medical problems, such as renal dysfunction, received rituximab and idelalisib versus rituximab and placebo.[17] With a median follow-up of less than 1 year, the PFS rate at 24 weeks favored the rituximab and idelalisib arm (93%) versus the rituximab and placebo arm (46%) (HR, 0.15; 95% CI, 0.08–0.28; P < .001), and the OS rate at 1 year was significantly better for the rituximab and idelalisib arm (92%) versus the rituximab and placebo arm (80%) (HR, 0.28; 95% CI, 0.09–0.86; P = .02).[17][Level of evidence: 1iA]

Ibrutinib is a selective irreversible inhibitor of Bruton tyrosine kinase, a signaling molecule located upstream in the B-cell receptor-signaling cascade. Trials of previously untreated patients and of patients with relapsed or refractory CLL showed durable responses to the oral agent in phase I and II studies.[18,19][Level of evidence: 3iiiDiii] A phase Ib–II trial (NCT01105247) of 85 patients with relapsed or refractory CLL showed a 26-month PFS rate of 75% and included patients with 17p- or unmutated IgVH fluorescence in situ hybridization testing.[20][Level of evidence: 3iiiDiii]

Oral alkylating agents with or without corticosteroids.[21] The French Cooperative Group on CLL randomly assigned 1,535 patients with previously untreated stage A disease to receive either chlorambucil or no immediate treatment and found no survival advantage for chlorambucil.[22][Level of evidence: 1iiA] A meta-analysis of six trials of immediate versus deferred therapy with chlorambucil (including the aforementioned trial by the French Cooperative Group) showed no difference in OS at 10 years.[8][Level of evidence: 1iiA]

Fludarabine, 2-chlorodeoxyadenosine, or pentostatin as seen in the CLB-9011 trial, for example.[23-28] Several randomized trials have compared the purine analogs with chlorambucil; with cyclophosphamide, doxorubicin, and prednisone; or with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) in previously untreated patients.[5,29-32] All of these trials showed higher or equivalent response rates for the purine analog, and most showed an improvement in PFS; one reached significance in OS favoring fludarabine.[3,29-33][Level of evidence: 1iiDiii]

A comparison of chlorambucil versus fludarabine, after 15 years' median follow-up, showed patients with improved median OS with fludarabine at 63 versus 59 months (P = .04) and an improved percentage of patients alive at 8 years (31% vs. 19%, P = .04).[3][Level of evidence: 1iiA] All of the trials demonstrated higher toxic effects with the purine analogs, especially granulocytopenic infections, herpes infections, autoimmune hemolytic anemia, and persistent thrombocytopenia.[34] The increased risk of infection may persist for months or years after treatment with a purine analog.[33,35]

Although empiric evidence is lacking, some investigators recommend prophylaxis with trimethoprim-sulfa during therapy and for 6 to 12 months afterwards to prevent pneumocystis infection. In a similar way, other investigators employ prophylaxis (e.g., acyclovir) for the herpes viruses.[35] Purine analogs cause less hair loss or nausea than combination chemotherapy, including alkylators and anthracyclines.[31]

Bendamustine is a cytotoxic agent with bifunctional properties of an alkylator and a purine analog.[36] In previously treated and untreated patients, bendamustine with rituximab has shown response rates around 70% to 90%.[37,38][Level of evidence: 3iiiDiii]

Lenalidomide is an oral immunomodulatory agent with response rates over 50%, with or without rituximab, for patients with previously treated and untreated disease.[40-45][Level of evidence: 3iiiDiv] Prolonged, lower-dose approaches and attention to prevention of tumor lysis syndrome are suggested with this agent.[40,46] Combination therapy and long-term toxicities from using lenalidomide (such as increased myelodysplasia, as seen in myeloma patients) remain undefined for patients with CLL.

Combination chemotherapy. A trial of 817 patients comparing FCR versus FC with a median follow-up of 38 months showed improved OS at 3 years for the rituximab combination (87% vs. 83%, P = .01).[4][Level of evidence: 1iiA] FCR has never been compared with watchful waiting up front in asymptomatic or minimally affected patients. The improvements in response rates from more intensive regimens have maximized the clearance of MRD. However, the surrogate endpoint of MRD clearance has not been proven to be a valid surrogate for improved survival in a randomized, prospective trial; the necessary study would take patients who fail to completely clear the marrow with induction therapy and randomly assign them to further alternative treatment versus the same treatment later at relapse looking at OS as the primary endpoint.[1,2] A cumulative incidence of 6% to 8 % for myelodysplasia is seen at 5 to 7 years in patients who received fludarabine plus cyclophosphamide, with or without rituximab.[47,48]

Fludarabine plus cyclophosphamide versus fludarabine as seen in the E2997 trial [NCT00003764] and the LRF-CLL4 trial, for example.[60,61]

Fludarabine plus chlorambucil as seen in the CLB-9011 trial, for example.[62]

A meta-analysis of ten trials comparing combination chemotherapy (before the availability of rituximab) with chlorambucil alone showed no difference in OS at 5 years.[8][Level of evidence: 1iiA]

Involved-field radiation therapy. Relatively low doses of radiation therapy will affect an excellent response for months or years. Sometimes radiation therapy to one nodal area or the spleen will result in abscopal effect (i.e., the shrinkage of lymph node tumors in untreated sites).

Alemtuzumab, the monoclonal antibody directed at CD52, shows activity in the setting of chemotherapy-resistant disease or high-risk untreated patients with 17p deletion or p53 mutation.[63-65] As a single agent, the subcutaneous route of delivery for alemtuzumab is preferred to the intravenous route in patients because of the similar efficacy and decreased adverse effects, including less acute allergic reactions that were shown in some nonrandomized reports.[65-69]

In a combination regimen, subcutaneous alemtuzumab plus fludarabine (with or without cyclophosphamide) or intravenous alemtuzumab plus alkylating agents have resulted in excess infectious toxicities and death, with no compensatory improvement in efficacy in phase II trials.[70-72][Level of evidence: 3iiiDiv]

Bone marrow and peripheral stem cell transplantations are under clinical evaluation.[76-82] In a prospective randomized trial, 241 previously untreated patients younger than 66 years with advanced-stage disease received induction therapy with a CHOP-based regimen followed by fludarabine.[83] Complete responders (105 patients) were randomly assigned to undergo autologous stem cell transplantation (ASCT) or observation, while the other 136 patients were randomly assigned to receive dexamethasone, high-dose aracytin, and cisplatin reinduction followed by either ASCT or fludarabine plus cyclophosphamide. Although the 3-year EFS favored ASCT in complete responders, there was no difference in OS in any of the randomized comparisons.[83][Level of evidence: 1iiDi]

Patients with adverse prognostic factors are very likely to die from CLL. These patients are candidates for clinical trials that employ high-dose chemotherapy and immunotherapy with myeloablative or nonmyeloablative allogeneic peripheral stem cell transplantation.[76-81,84-91] Although most patients who attain complete remission after ASCT eventually relapse,[82] a survival plateau for allogeneic stem cell support suggests an additional graft-versus-leukemia effect.[91] A series (NCT00281983) of 90 patients with relapsed or refractory CLL who underwent ASCT reported a 58% 6-year OS rate and a 38% 6-year EFS rate, which included those patients with the worst prognostic factors (such as TP53 gene mutation).[92][Level of evidence: 3iiiD]

Autologous T-cells were modified by a lentiviral vector to incorporate antigen receptor specificity for the B-cell antigen CD19 and then infused into a previously treated patient.[93] A dramatic response lasting 6 months has prompted larger trials of this concept.[93][Level of evidence: 3iiiDiv] Ongoing clinical trials are testing the concept of T-cells directed at specific antigen targets with engineered chimeric–antigen receptors (termed CARs).[94]

Is the CHOP regimen a good treatment for advanced CLL? Results from two randomized clinical trials. French Cooperative Group on Chronic Lymphocytic Leukemia. Leuk Lymphoma 13 (5-6): 449-56, 1994. [PUBMED Abstract]

Recurrent or Refractory CLL

Clinical trials are appropriate and should be considered when possible.[1] In small studies, response rates of more than 40% have been reported for lenalidomide [2-4] and flavopiridol.[5,6][Level of evidence: 3iiiDiv] The addition of the Bcl-2 anti-sense oligonucleotide oblimersen to fludarabine/cyclophosphamide improved complete response rates in a randomized study of 241 patients with relapsed disease.[7][Level of evidence: 1iiDiv] Bone marrow and peripheral stem cell transplantations are under clinical evaluation.[8-14]

Current Clinical Trials

Check for U.S. clinical trials from NCI's list of cancer clinical trials that are now accepting patients with refractory chronic lymphocytic leukemia. The list of clinical trials can be further narrowed by location, drug, intervention, and other criteria.

General information about clinical trials is also available from the NCI Web site.

References

Byrd JC, Rai KR, Sausville EA, et al.: Old and new therapies in chronic lymphocytic leukemia: now is the time for a reassessment of therapeutic goals. Semin Oncol 25 (1): 65-74, 1998. [PUBMED Abstract]

About This PDQ Summary

Purpose of This Summary

This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the treatment of chronic lymphocytic leukemia. It is intended as a resource to inform and assist clinicians who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.

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